import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;


/**
 * This program displays a greeting from the authors.
 * 
 * @version 1.20 2004-02-28
 * @author Cay Horstmann
 */
public class Fangzhuangjia {

	   public static void main(String[] args) throws FileNotFoundException
	   {
		   
		   
		   File f = new File("a.txt") ;
		   
	       Scanner in = new Scanner(  f  );
	       
	       int oneInt =0;
	      
	      	       
	       while( in.hasNext()  ){
	    	   String line = in.nextLine();
	    	   char one = line.charAt(0);
	    	   char two = line.charAt(2);
	    	   
	    	   System.out.println("one: " +one);
	    	   System.out.println("two: " +two);
	    	   
	    	   oneInt = oneInt + Integer.parseInt(one+ "");
	    	   
	    	   
	       }
	       System.out.println(oneInt/2);
	   }

}
